The present invention relates to speed controlling devices, and more particularly to a speed controlling device which makes a motor speed follow a set speed value varying with the passage of time.
In a conventional speedometer system for a vehicle, a meter cable is laid between an axle and a meter pointer. One end of the meter cable is connected integrally with and rotated by the axle, and the other end thereof is connected by way of an eddy current coupling to the meter pointer in order to move the pointer according to the rotating speed of the axle, i.e. the running speed of the vehicle. In this system, a space for laying the meter cable is required and moreover the fatigue of the cable itself must be taken into account as another problem.
If the rotating speed of the motor can accurately follow that of the rotating body such as the above-mentioned axle whose rotating speed varies with the passage of time, the meter pointer may be connected to the motor by way of the eddy current coupling whereby the compact and highly reliable speedometer without using any meter cable is available.